From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1F24DEB48EA for ; Thu, 12 Feb 2026 09:03:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=okszUF6rn81wokN6MFCx8nZtl6u7oamXEuCUR6T4heI=; b=PkDhgAkshLlulKo6D25dNohKqv AXerMZaV3YBHY2ZLNxZUErdT0Pwm9vUd0bPsg3nE4SM4IJmrwBOOYjB6MGGxm8imJMLt2pBzgBw55 0g6rwiQlJ4DydNqeCRhiV3E/rO+8G0yTXrovn53FAFWLs46E8FPIiduRnpNj4BWGMZJprTAj6zpbW LiuQG7zQrd2uTWdca30CxEQW6BaNUuQQ21kMZfY8aFXl4AcyW+5K0Ql3deTzu3hR1djkg/jIEo8O5 HOm/ZiT/4VSqfpHCXq/OPTq6ISDaWVIV6S8j8HRLYI/h9Y2V+zX48nZ1oej4jEKPbCu8zxtHRYCHC 9J7gjdog==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vqSbF-00000001ngL-3OJm; Thu, 12 Feb 2026 09:03:01 +0000 Received: from mail-wr1-x44a.google.com ([2a00:1450:4864:20::44a]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vqSbB-00000001neE-3eUJ for linux-arm-kernel@lists.infradead.org; Thu, 12 Feb 2026 09:03:00 +0000 Received: by mail-wr1-x44a.google.com with SMTP id ffacd0b85a97d-43630b02fb4so4875138f8f.3 for ; Thu, 12 Feb 2026 01:02:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1770886975; x=1771491775; darn=lists.infradead.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=okszUF6rn81wokN6MFCx8nZtl6u7oamXEuCUR6T4heI=; b=hLPCm9IoVdM1dSJ5tNcrUnKkG4kgCAy2ZZ8/ssLRfThxMiQpHn3vQCjwh5BU8bgN+J SxUzSGaLDDt96LjBsxTGOm+0YMbEr7FnIZzuhwqcL7EtWrOOour6u/hx9nL6sAWreKWW PjBb0IRT7IOj/You6xSUc8Wi0rnU9k4ZIXZJxJIor9resbHPWY7nwS6Xz7MKoUGvFd7u leXeYmktkCcFxaK8NQqIASm1aY/ma3sYIfkP5iNwUKoC+PaKbU/Nl3w2suDhTaWHZ0pW XK+jNzxlyDns5SX7hJ4H9EfoNeZYJtwnzIPINIyc0SJgfjnjjIAHhNuHbr3qlJC4zoVg dLzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770886975; x=1771491775; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=okszUF6rn81wokN6MFCx8nZtl6u7oamXEuCUR6T4heI=; b=SQwxjbuikVI6cJz7ydfQD9QBsuw2K77T1VClv61skqvKSH8GkxZf0KUMSjFBfPlSHN ZQDdjhkLQtNrAhlPld0CqIH3VG8Fiz/RM7rLkKjKqEPCafEJMiOH3is+2We3+UQPy4q6 IYRn7Wdshssg+/AZ8Dwt3RB2lN83yVe3tpumG33eTffBrdixSkO3pKBJBi6XeoHlWzOC jtrRjlFLQGk3MZmSARQ6NFnxEN3kdUIX1Mv6iLzsIc9kKXfQecDEqYCl6xhXnpiZAhXG edayt1DTaJqRxucGz6NqbYaQsFBE+Rv6Qsu1Vt1C91/9XOOLq12IeUxvhgCKQ7oxE4NU X6Cg== X-Forwarded-Encrypted: i=1; AJvYcCUOihbo1QlJYS+ZdoOcJCaABF4bIx1gG9ol8+hpe5jjB69K6JWLIw76jK2qGf/g7TkdnX0csLen2IPbWPnoRNvV@lists.infradead.org X-Gm-Message-State: AOJu0YxHyevOPLjJ42LUQL52xINmMawSi8gyHSSrxxojCnb1rlud6niZ K15+L7qNqmpzV8eEYp+DqQfzx+JYuJpVoyKdfjW2rIF4njxGCersZg7IRgVWLdmAL23yE1Cw2XE nQw== X-Received: from wrbfv12.prod.google.com ([2002:a05:6000:2c0c:b0:437:72d9:7316]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a5d:5f48:0:b0:436:3475:3687 with SMTP id ffacd0b85a97d-4378adca042mr3331122f8f.57.1770886975548; Thu, 12 Feb 2026 01:02:55 -0800 (PST) Date: Thu, 12 Feb 2026 09:02:51 +0000 In-Reply-To: <20260212090252.158689-1-tabba@google.com> Mime-Version: 1.0 References: <20260212090252.158689-1-tabba@google.com> X-Mailer: git-send-email 2.53.0.239.g8d8fc8a987-goog Message-ID: <20260212090252.158689-3-tabba@google.com> Subject: [PATCH v1 2/3] KVM: arm64: Fix ID register initialization for non-protected pKVM guests From: Fuad Tabba To: kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, tabba@google.com, stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260212_010257_923919_980F5E54 X-CRM114-Status: GOOD ( 16.93 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In protected mode, the hypervisor maintains a separate instance of the `kvm` structure for each VM. For non-protected VMs, this structure is initialized from the host's `kvm` state. Currently, `pkvm_init_features_from_host()` copies the `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the underlying `id_regs` data being initialized. This results in the hypervisor seeing the flag as set while the ID registers remain zeroed. Consequently, `kvm_has_feat()` checks at EL2 fail (return 0) for non-protected VMs. This breaks logic that relies on feature detection, such as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain system registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not saved/restored during the world switch, which could lead to state corruption. Fix this by explicitly copying the ID registers from the host `kvm` to the hypervisor `kvm` for non-protected VMs during vCPU initialization, since we trust the host with its non-protected guests' features. Also ensure `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in `pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly initialize them and set the flag once done. Fixes: 41d6028e28bd ("KVM: arm64: Convert the SVE guest vcpu flag to a vm flag") Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/nvhe/pkvm.c | 37 ++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 12b2acfbcfd1..267854ed29c8 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -344,6 +344,8 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc /* No restrictions for non-protected VMs. */ if (!kvm_vm_is_protected(kvm)) { + clear_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &host_arch_flags); + hyp_vm->kvm.arch.flags = host_arch_flags; bitmap_copy(kvm->arch.vcpu_features, @@ -471,6 +473,36 @@ static int pkvm_vcpu_init_sve(struct pkvm_hyp_vcpu *hyp_vcpu, struct kvm_vcpu *h return ret; } +static int vm_copy_id_regs(struct pkvm_hyp_vcpu *hyp_vcpu) +{ + struct pkvm_hyp_vm *hyp_vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu); + const struct kvm *host_kvm = hyp_vm->host_kvm; + struct kvm *kvm = &hyp_vm->kvm; + + if (!test_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &host_kvm->arch.flags)) + return -EINVAL; + + if (test_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags)) + return 0; + + memcpy(kvm->arch.id_regs, host_kvm->arch.id_regs, sizeof(kvm->arch.id_regs)); + set_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags); + + return 0; +} + +static int pkvm_vcpu_init_sysregs(struct pkvm_hyp_vcpu *hyp_vcpu) +{ + int ret = 0; + + if (pkvm_hyp_vcpu_is_protected(hyp_vcpu)) + kvm_init_pvm_id_regs(&hyp_vcpu->vcpu); + else + ret = vm_copy_id_regs(hyp_vcpu); + + return ret; +} + static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, struct pkvm_hyp_vm *hyp_vm, struct kvm_vcpu *host_vcpu) @@ -490,8 +522,9 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, hyp_vcpu->vcpu.arch.cflags = READ_ONCE(host_vcpu->arch.cflags); hyp_vcpu->vcpu.arch.mp_state.mp_state = KVM_MP_STATE_STOPPED; - if (pkvm_hyp_vcpu_is_protected(hyp_vcpu)) - kvm_init_pvm_id_regs(&hyp_vcpu->vcpu); + ret = pkvm_vcpu_init_sysregs(hyp_vcpu); + if (ret) + goto done; ret = pkvm_vcpu_init_traps(hyp_vcpu); if (ret) -- 2.53.0.239.g8d8fc8a987-goog